P20011: Articulating Toilet System
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Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

During this phase, our team hoped to complete all MSD 1 documentation as well as the CAD files essential to our design. We hoped to have these designs assembled and have a finished CAD model of the prototype by the end of this phase. A stretch goal for the team is to design cardboard prototypes of the intended components.

In addition to this, the team planned to complete human testing training and submit a human test plan to the IRB for review. We also planned to understand any additional budgetary needs through the completion of our BOM and hoped to submit a budget increase request by December 5th.

Below is a hierarchy of items that we planed to accomplish in the next phase. Items at the top show the most risk, items at the bottom are likely to be accomplished without issue.

Figure 4.1: Action Items

Figure 4.1: Action Items

In order to accomplish these goals the team will adhere to the schedule below:

Figure 4.2: Phase 4 Project Flowchart

Figure 4.2: Phase 4 Project Flowchart

Figure 4.3: Phase 4 Project Flowchart

Figure 4.3: Phase 4 Project Flowchart

During this phase of the project, our team was able to complete the design for the system base, hydraulics, seat, torso support, and arm supports of the intended system. We struggled unexpectedly with the details of the back support, but have successfully come to a consensus of a solution that we believe will be suitable given the goals of the team. By completing all of the design components, our team was also able to complete our BOM. We were also able to develop plans we hope to adhere to to manufacture this product and rough plans for the beginning of MSD 2.

In addition to the design work outlined above, our team was able to accomplish many of the clerical tasks required to close out this design phase. This included submission of the human test plan to the IRB as well as the successful completion of human testing training by all of the project team members. Finally, our team worked to update the edge page and ensure all documentation from previous phases was successfully closed out and posted in the appropriate locations.

Progress Report

Our team sent out a status report on 11/26 to provide our guide and customer with an update. The below section details the progress that the team had made in comparison to the plan outlined in the section about. This report shows the progress of the project as of 11/26. This status report was sent to both to the project team members and our guide Art with the note to forward the report to any parties of interest if needed.

As of 11/26 our team was able to accomplish the following objectives:

  1. Completed Human Testing Training
  2. Updated all documentation from previous phases
  3. Completed human test plan
  4. Updated team edge page for all previous phases
  5. Completed model for arm and torso supports

The remaining tasks for this project phase to be considered successful are as follows:

  1. Complete BOM
  2. Request Budget Increase
  3. Complete modelling of the back support
  4. Complete the team edge page for this design phase
  5. Submit Human Testing Plan to the IRB

Following the last design review, the team made the decision to remove the tilt feature from our model. Following this decision minor reworks of the design were needed, however as of current the team is on track to complete MSD 1 successfully with a complete model by the end of the semester.

As of current the team has no further questions

Team progress reports will also be posted here

Finalized Design and Structural Analysis

The detailed design of the system was finalized during this phase. Several design changes were made based on feedback from the preliminary design review, including simplifications to make the design less intimidating, the removal of the tilting functionality, and less thin plates being welded over long distances.

The system flowchart as well as the hydraulics diagram were updated to reflect these changes.

Figure 4.4: Finalized System Flowchart

Figure 4.4: Finalized System Flowchart

Figure 4.5: Finalized Hydraulic Diagram

Figure 4.5: Finalized Hydraulic Diagram

The finalized design geometry is shown in the images below.

Figure 4.6: Overall Isometric View

Figure 4.6: Overall Isometric View

Figure 4.7: Overall Lower Isometric View

Figure 4.7: Overall Lower Isometric View

Note that the base of the system is now rectangular box tube rather than flat plate to avoid the material warping during welding. Additionally, with the removal of the tilting functionality, the lift pistons were able to be moved towards the rear of the system and the overall seat design was simplified.

Figure 4.8: Frame Isometric View

Figure 4.8: Frame Isometric View

Figure 4.9: Seat Isometric View

Figure 4.9: Seat Isometric View

Figure 4.10: Seat Bottom View

Figure 4.10: Seat Bottom View

Figure 4.11: Guide Bearing Detailed View

Figure 4.11: Guide Bearing Detailed View

As shown in the picture above, the seat is constrained by bearings that run along the vertical guide bars. The bearings are mounted onto shoulder bolts that are fastened to the seat structure, which prevents seat motion in all direction except for vertical translation. A large crossbar was implemented to improve overall system stiffness to ensure the pistons and bearings stay aligned to minimize any binding due to misalignment.

Figure 4.12: Piston Isometric View

Figure 4.12: Piston Isometric View

Figure 4.13: Piston Exploded View

Figure 4.13: Piston Exploded View

Figure 4.14: Piston with Arm and Torso Supports

Figure 4.14: Piston with Arm and Torso Supports

In regards to the hydraulic cylinders, much of the design has been carried over from the previous year's prototype with changes implemented as needed. Overall, the cylinder's construction is nearly identical, in fact the team will be reusing the brass piston plug at the bottom of the cylinder with an adapter to new mounting system. The piston and o-ring sizing was updated based on the calculations presented in the preliminary design review. The remainder of the hydraulic system, such as the fitting, valves, and hosing will also be carried over from the previous year's prototype.

As this system was being designed, the team kept manufacturing in mind by maintaining standardized tube sizes across multiple components so that the same stock material could be used. Calculations were done to ensure that the tubing was appropriately sized to avoid excessive deflection or stress that would lead to user discomfort or system failure. These calculations are shown in the images below.

Figure 4.15: Round Tube Calculations

Figure 4.15: Round Tube Calculations

Figure 4.16: Round Tube Dimensions

Figure 4.16: Round Tube Dimensions

Figure 4.17: Square Tube Calculations

Figure 4.17: Square Tube Calculations

Figure 4.18: Square Tube Dimensions

Figure 4.18: Square Tube Dimensions

These calculations account for the components that are subject to the highest structural risk, including bending stress, bending deflection, and shear stress of the piston mount tubes as well as bending stress, and bending deflection of the seat reinforcement tubes.

Manufacturing and Assembly Plan

The below plan details the intended manufacturing plan for the W.A.R.4 Team Articulating toilet design. This design includes a prototype that lifts and lowers to meet user need, and has adjustable arm supports to assist users in transfer from chair to toilet. As the team further develops this plan this document will change until it reaches its final version which will document the actual manufacturing plan used at the end of MSD 2. It is the intent of the team that the document will resemble the current state at the end of the design, but there are risks recognized that may inhibit us from utilizing the manufacturing plan.

For full access to the manufacturing plan document click here.

This manufacturing plan was developed in accordance to the BOM listed on the HOME page of this website, as well as in accordance with the manufacturing drawings shown below. The intent of the team is to pass these drawings on to the Lab in MSD 2 when our components need to be water jet.

Figure 4.19: Prints Prepared for the Manufacturing Phase

Figure 4.19: Prints Prepared for the Manufacturing Phase

The complete set of manufacturing prints can be found here

Moving into the design phase, our team recognized that much of this documentation is subject to change, and for this reason we have not yet created a user manual. Our intent is to complete this document during the build phase while some of the more detailed use information is finalized.

For full access to the assembly plan document click here.

Bill of Material (BOM)

The completion of the material design resulted in the ability for a more complete bill of materials to be developed. This bill of materials includes the main materials needed to manufacture the majority of our prototype. It also includes a cost estimate for the different hardware that will be required in order to assemble the prototype. This list of hardware includes screws, bolts, nuts, washers, bearings, etc.

Figure 4.20: P20011 Steel Tubing Raw Material Calculations

Figure 4.20: P20011 Steel Tubing Raw Material Calculations

Shown above in Figure 4.20 is a breakdown of the different "tubing" materials that the team is going to look into purchasing. Through a structural analysis, we were able to determine appropriate dimensions for the different components located within the prototype. We then created a list of desired tubing material and found everything that we needed on OnlineMetals.com. These different products, which we plan to purchase from OnlineMetals.com were then linked to the different prototype components, along with the corresponding part numbers. We plan on cutting the purchased parts to their desired part number dimensions once they arrive.

Figure 4.21: Plate Raw Material Calculations

Figure 4.21: Plate Raw Material Calculations

Figure 4.21 shows a breakdown of all the brackets and plates that are essential for the construction of the final prototype. These different components and part numbers were linked to a steel plate that was found on OnlineMetals.com. Once the plate is ordered and has arrived, our plan is to use it for manufacturing the different brackets and plates ourselves. While the tubing calculations were found by using part number length, these were completed using part number area. We got in contact with OnlineMetals.com to get lead time estimates for all of the materials that we plan on purchasing from them. We were told that the materials would take about 2-3 business days for shipping.

Figure 4.22: P20011 Bill of Materials (Revision #2)

Figure 4.22: P20011 Bill of Materials (Revision #2)

Lastly, Figure 4.22 is our bill of materials spreadsheet. The quantities of the different part numbers were found by calculating what percentage of the purchased material length each part number is responsible for. That quantity was then multiplied by the amount that was paid for the material that makes up this part number. The live document for the bill of materials list can be viewed here.

The total current estimate for materials is $482.19. These values are estimated before tax and it is estimated that our team will need to purchase additional materials we have not accounted for yet, as it is understood that as the design develops we will encounter unforeseen issues. It should also be noted that the hardware list is likely going to change throughout the duration of MSD 2, which will definitely impact and affect this initial final cost estimate of $482.19. This final cost estimate also does not take into account that the team is almost definitely going to need to purchase a new set of pistons for the hydraulic system. These pistons will add to the cost of our prototype.

Given these costs, and the expectation that additional costs will be accrued throughout the project life cycle. Our team is going to request an additional $500 for the completion of this project.

Test Plans

Figure 4.23: The non-human test plan document focuses on how we are going to test 5 different functions of the design.

Figure 4.23: The non-human test plan document focuses on how we are going to test 5 different functions of the design.

As mentioned in the previous phase, our team developed six different plans to test the functions of the device. These test plans include: functionality, hygiene, piston leakage, safety, static load capacity, and visual appeal/human testing. Each test plan contains sections for detailed testing specifications (function tested, specification tested, unit of measure, and margin of error), equipment required for testing, a data collection strategy, procedure for testing, tables for data collection, and space to record any observations or conclusions we can draw from the test.

Since the last project phase, our team determined there were two changes in the test plans since last reported on.

First, the team decided in the last design review that the tilting feature of our model would no longer be needed, this resulted in the removal of the tilting testing from our test plans. In addition, our team decided we did not need to create as specific test plan for human testing, as it is likely our safety test on the product would suffice. Given these conclusions our team submitted the safety test to the IRB for testing approval.

All test plans can be found here.

Risk Assessment

During this phase of the project, our team was able to identify risks that have been realized, and risks that have been significantly minimized. Moving into this phase of the project, our team has identified 10 new risks that would prevent us from successfully closing out MSD 1 and would hinder our progress in MSD 2. This brings the total number of risks for MSD 1 to 75.
Figure 4.24: P20011 Risk Analysis (Revision #4)

Figure 4.24: P20011 Risk Analysis (Revision #4)

To view the live risk management spreadsheet, click here.

Plans for next phase

Following this phase of the project, our team has set out to complete our Gate review which has been scheduled for Tuesday, 12/10. Our team will be preparing for this gate review by accomplishing the remaining tasks on our team Monday account shown below.
Figure 4.25: To do Before Gate Review

Figure 4.25: To do Before Gate Review

Figure 4.26: To do Before Gate Review Flow Chart

Figure 4.26: To do Before Gate Review Flow Chart

In order to prepare for MSD 2 our team needs to ensure that all of the action items from this design review are followed up on - and the above list of action items are complete. Below you can find a list of what each team member homes to accomplish before the gate review.

Finally, in order to prepare for the next phase of the project, our team has developed the below schedule for MSD 2, this as many other schedules s subject to change as we develop a more detailed build plan.

Figure 4.27: Tentative schedule for MSD II

Figure 4.27: Tentative schedule for MSD II

Design Review Materials

Include links to:

Three Week Plans

  1. Christina Eker
  2. Samantha Destremps
  3. Daniil Sushko
  4. Marlon Naveda
  5. Kristina Klishko

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